I haven't trade any coins there yet, but my friend said you must have at least 0.05 - 0.1 eth. You must prepare enough gas to buy any coins on Uniswap, mate.
0.05eth is worth only for fee. Also you must trade 1 eth higher in order to have a good profit when youre lucky. The fees now on uniswap are ridiculously high so below 1eth trade is not worth it cause you need to prepare at least 10$ average fee for every trades. So I think uniswap is not for small traders, better to use cex for that.
You can trade on centralized exchanges where you don't need to pay network fees. If you are trading large amounts, it will not be a problem for you to pay a Commission of 10-20 dollars. This forces you to evaluate your profit before trading.